Porosity describes open space within a material; permeability describes how readily water passes through connected spaces. Pumping can lower groundwater levels when removal exceeds replenishment. This grain-and-pore model is a simplified example: fractured rock and some cave systems store and transmit groundwater differently. Recharge adds water to groundwater storage; pumping removes it through wells.
Water and oceans · Discover & try
How can the ground hold water?
Reading level 5 of 5 · AdvancedChange
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water table
The upper boundary of the groundwater-saturated zone.
aquifer
Rock or sediment that stores and transmits usable groundwater.
porosity
The proportion of a material occupied by open spaces.
permeability
How readily water can move through connected openings.
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Simplified grains, pores, and water table; flow rates are illustrative rather than site measurements.
What to look for
- Water between solid grains
- Connected and disconnected spaces
- The water table changing with recharge or pumping
Explain what you noticed
Where is groundwater commonly stored?
Keep this idea: Groundwater commonly fills pores and fractures within solid ground.
Follow the sources
- U.S. Geological Survey — Groundwater: What is Groundwater?
- U.S. Geological Survey — Aquifers and Groundwater
- U.S. Geological Survey — Groundwater Decline and Depletion
Source material checked 2026-10-28. Explanations and activities by Nepedia. Agency source links do not imply endorsement.
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